Process and apparatus for treating storage-battery plates



H. M. MARTIN. PROCESS AND APPARATUS FOR TREATING STORAGE BATTERY PLATES.

APPLICATION FILED A PR.6,1920. 1,%02,681.

Patent ed Jan. 3, 1922.

M m m M NJ A M M M D mw fi R A HAROLD M. MARTIN, OF NEW YORK, .N. Y., ASSIGNOR T0 PHILADELPHIA. STORAGE BATTERY COMPANY, 013' JPHILADELPHIA, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

IPRQCESS AND APPARATUS FOR TREATING STORAGE-BATTERY PLATES.

1,ed2,63i.

Application filed April 6,

To all whom it may concern:

Be it known that I, HAROLD M. MARTIN, a citizen of the United States, and a resident of New York city, in the county of New York and State of New York, have invented certain new and useful Improvements in Processes and Apparatus for Treating Stop age-Battery Plates, of which the following is a specification.

This invention relates to the manufacture This treatment results in a plate of pure spongy lead that, if kept dry, can be transported and stored without need for recharging prior to assembly of the battery. The negative plates as described in the pat ent referred to are in a practically metallic state and structurally in a crystalline and sponge like form that offers the desirably large active surface relative to the size of the plate.

These dry battery plates when subjected to the rough treatment which is sometimes experienced in commercial handling, packing, boxing and transportation may have portions of the active metal broken awa from the supporting parts of the plate whic i is, of course, undesirable.

By my invention, I provide a process of treatment which can be readily and expedi tiously carried out upon the dry negative plates mentioned in the foregoing, for the purpose of materially strengthening thev leadplates and rendering them less brittle without, however, in any way diminishing the capacity of the battery of which these plates are to be a part.

It will be understood that my, improved methodis applicable to the treatment of dry ne ative plates regardless h'ow made and dried, though the process is preferably carried out upon negative plates previ- Specification of Letters Patent.

Patented J amid, 1922. 1920. serial No. 371,755.

ously treated according to the specific method made the subject-matter of my petout above referred to.

ln its essence my process consists in applymg in intimate contact with parts of the surface of the plate, some substance which will strengthen the plate structure. It will be understood that by the-term surface as used in certain of the claims, I mean those parts of the plate which are reached by the electrolyte, including not only the area that may be touched by the hand but the superficial area of the pores in the plate as well.-

The substance for strengthening the structure of the plate should preferably partially fill some or all of the pores of the plate.

A variety of substances may be used for strengthening the plate structure. For instance, I may employ a material applied upon the plates in the form of a liquid or.

paste having the property of subsequently hardening in contact with the surface and particularly in the pores Glue or plaster of aris will serve for this purpose by way of example. As another alternative Imay provide a mixture of substances which would react upon each other chemically to deposit a substance that will react chemically upon parts of the surface of the plate to produce particularly within the pores a formation a compound of lead which has the required physical strength.

- Whatever substance is used for strengthening the structure of the plate and by whatever process the same may be applied the strengthening formation should be of a,

character such that it will not be attacked by the atmosphere to destroy or impair its.

eilicac while the plate is being shipped or store in dry state. Thestrengthen ng formation performs its main function while the plates are being shipped or stored in dry state. I prefer to provide the strengthenmg formation of a material substantially insoluble in the electrolyte and chemically inert theretobut it is apparent that the iiimal operation or life of the battery. The physical formation of the strengthening subv stance is preferably one of considerable comstruction the new negative plate has a large capacity above'that which is necessary to discharge the corresponding positive plate. In carrying out my process particularly where the strengthening formation to be deposited or generated is impervious to the electrolyte, I apply such formation to such fraction of the totalsurface of the plate as to leave uncovered and exposed to theaction of the electrolyte sufficient of the negative plate surface to completely discharge the positive-plates. By this means although I reduce the active surface of the negative plates it is excess surface only that is eliminated and this for the useful purpose of aining strength and reducing brittleness. The capacity of the battery is in no way diminished as this capacity is equal to that necessary to discharge the positive plates and this capacity remains the same as that, of a' battery of similar construction not subr j'ected to my new. process.

A preferred embodiment of my process consists in applying to the surface of the plates dilute sulphuric acid preferably in the form of a fine spray or mist. This process is carried out in the pre'senceof air whereby the active leadmetal will become sulphated where touched by the acid, the sulphate of lead tending to fill thepores of the'active metal and cover other parts of the platetb-aiford the mechanical support f as distinguished-from the pores 'of'the active metal would be sulphated, the sulphate act- 'ingto support and-contain the unchanged desired.- This process mi ht be so arranged that only' a fraction of t e out. .ide surface spon metal inside of it, or again, approxir matey, the same proportion of the surface active material might be acted upon in en-; eralthroughout the whole surface inclu ing that of the pores, thus producing the effect of strengthenin ture of the active metal as a whole. 'In' and hardening the strucwhichever manner the process is carried out,

it is important that'the sulphating action be time or in the same container, it will be ap The excess surface of the negative plate in commercial practice is sufficiently large to permit material strengthening of the negative plate where the sulphating action is confined to the excess proportion of. the total area of the negative surface including that of the pores.

In the accompanying drawings I have shown diagrammatically an apparatus for carrying out my preferred process. In the drawings 1 represents a belt or similar con- 'veyance connected with clamps 2 so arranged that they can be quickly and readily attached to the lugs 3 of the negative plates 'of the negative plates asthey are passed I along by moving the belt 1 at an appropriate rate of speed. In practice, the spray will be produced with such intensity and the belt shifted at'a rate of speed such as to cause the formation of the lead sulphate upon an appropriate fraction of the total surface area not greater than the excess beyond that I required to discharge the positive. 10o

I have It will be understood that although specifically disclosed a method of treating storage batter plates previously dried by the process 0 my patent-No. 1,310,871 or some other equivalent process, the drying and the strengthening treatment might if desired be carried on. simultaneously." Where theplates-are dried and the sulphuric acid is sprayed upon the surface at the same parent that the acid being itself a drying agent will assist the drying rocess while also acting upon the lead chemically to fprm the strengthening sulphate.

I claim:

1. The process of treating negative stor age battery plates fog-increasing the me-v chanical strength thereof, which consists in disposing a mechanically stronger substance into intimate ,ontact face area thereof. I

2. The process of treating-negative 'stor age'battery plates for. increasing the mechanical strength thereof, which consists in disposing a mechanically stronger substance 125 within pores of the plate, and into intimate contact therewith.

3. The process of treating negative storage batt'ery plates to mechanically strengthen them for dry storing and shipping, which 30 with parts of thesurconsists in applying thereto a medium for causing the generation of relatively hard and strong surface formations upon the plate inert to the electrolyte to be employed.

e process of treating the active material of negative storage battery plates when in a dry and almost wholly metallic state, which consists in applying thereto a medium that will enter the pores and generate therein relatively hard and strong formations inert to the electrolyte to be employed.

5. The process of treating negative storage battery plates for increasing the me chanical strength thereof, which consists in disposing a mechanically strongersubstance into intimate contact with parts of the surface area thereof, leaving exposedto the electrolyte when in use suilicient area to discharge the corresponding positive plate.

6. The process of ti-eating the active material of negative storage battery plates when in a dry and almost wholly metallic state, which consists in applying thereto, a medium that will enter the peresand generate therein. relatively hard and strong formations theprocess being carried out to an extent to leave exposed to the electrolyte when the battery is assembled sufficient active area to discharge the corresponding positive plate.

7. The process of treating the active ma terial of negative storage battery plates when in a dry and almost wholly metallic state, which consistsin performing at the surface thereof a chemical reaction of a character to produce a formation of a relatively hard and strong substance in intimate battery is assembled suflicient active area to discharge the corresponding positive plate.

he process of treating the active-material of negative storage battery plates when in a dry and almost wholly metallic state, which consists in applying thereto sulphuric acid to sulphate the surface of said plate to'a degree to leave exposed to the electrolyte when the battery is assembled sailicient active area to discharge the corresponding positive plate.

he process of treating the active material of negative storage battery plates when in a dry and almost wholly metallic state, which consists in spraying thereon sulphuric acid in the presence of air, to form lead sulphate in the pores of the plate, said process being continued to a degree to leave exposed to the electrolyte when the battery is assembled suiiicient active surface area to discharge the corresponding plate.

Signed at New York in the county of New ork and State of New York, this 3rd day of April, 1920, A. D.

- HAROLD M. MARTIN. 

